How to Fix a Crossbite: Causes, Treatment Options, and Cost
A crossbite is a bite in which one or more upper teeth close inside the lower teeth instead of outside them. It is corrected by widening the upper arch with an expander, or by moving individual teeth with braces or aligners. Correcting it in childhood is far simpler than in an adult, because the palate is still widenable.
Dr. Jenée Kaplan, DDS
Orthodontic residency and a Master’s degree at Loma Linda University. Member of the American Association of Orthodontists, the American Dental Association, and the California Dental Association.
What is a crossbite?
The upper arch is meant to sit slightly outside the lower arch the whole way round, like a lid on a box. A crossbite is a place where that relationship inverts. At the back it is a posterior crossbite, usually from an upper arch that is too narrow. At the front it is an anterior crossbite, which is a localised underbite involving one or a few teeth.
The important thing a crossbite does is make the patient shift the jaw to close comfortably. Faced with teeth that collide, the jaw slides sideways into a position where they fit. That shift becomes habitual, then becomes the way the muscles and joint are trained to work, and in a growing child it can make the lower jaw develop asymmetrically.
This is why a crossbite gets treated earlier than most conditions, and why it is treated even when it involves only one tooth. It is not the crossbite itself that does the harm so much as the compensation it forces.
What causes a crossbite?
- A narrow upper jaw
- The usual cause of a posterior crossbite. The palate did not develop to full width, so the upper arch is simply too small to sit outside the lower one.
- Mouth breathing and low tongue posture
- The tongue resting against the palate is part of what widens the upper arch during growth. A child who breathes through the mouth holds the tongue low and the lips apart, and mouth breathing is consistently associated with a narrower upper arch — one factor among several rather than the whole explanation. Enlarged tonsils and adenoids and chronic allergy are common contributors, and they belong in the conversation with a physician, not just an orthodontist.
- Crowding and eruption path
- A tooth with nowhere to go erupts wherever there is space, sometimes inside the arch. A single tooth in crossbite is often no more than an eruption accident.
- Retained baby teeth and early loss
- A baby tooth that will not come out deflects the adult tooth behind it. One lost too early lets neighbors drift into the space. Both can put a permanent tooth on the wrong side of the bite.
Why does an untreated crossbite matter?
- Asymmetric jaw growth. In a growing child, a habitual sideways shift to close can produce a genuine facial asymmetry over years. That is the reason pediatric crossbites are not simply watched.
- Joint and muscle load. A jaw that works from a shifted position loads the joint unevenly. Crossbite is the bite pattern most consistently associated with later jaw joint symptoms — though association is not cause, and the jaw pain page sets out what the evidence actually supports.
- Gum recession. A lower tooth trapped outside the upper arch, or an upper tooth inside it, sits at the edge of its bone. The gum over it thins and retreats, exposing root surface that is sensitive and prone to decay.
- Localised wear and chipping. Teeth in crossbite hit each other on surfaces not shaped for contact. Chipped cusps and flattened edges show up early.
- Chewing on one side. Many patients with a posterior crossbite chew almost entirely on the unaffected side without ever having decided to.
How is a crossbite treated?
Palatal expander
A fixed appliance across the roof of the mouth, widened a fraction of a turn at a time, that separates the two halves of the upper jaw at the midline suture and lets new bone fill in. It takes a few months of activation and then a period of holding while the bone consolidates.
Who it suits: The definitive correction for a narrow upper jaw, and dramatically easier before the palatal suture fuses in the early teens. In adults the same widening needs surgical assistance, which is the single best argument for treating a posterior crossbite in childhood.
Braces
For a crossbite involving one tooth or a few, braces move the offending teeth across the bite into a correct relationship, sometimes with a temporary bite plate so the teeth clear each other while they move.
Who it suits: Single-tooth and anterior crossbites at any age, and the finishing stage after an expander has created the width. Cannot by itself widen a jaw — brackets move teeth, not bones.
Clear aligners
Aligners correct many single-tooth crossbites and can produce modest arch widening by tipping teeth outward. Attachments and elastics extend what they can manage.
Who it suits: Mild dental crossbites in a reliable tray wearer. Tipping teeth outward is not the same as widening a palate, and using aligners where an expander is indicated buys a cosmetic result on an uncorrected foundation.
Surgically assisted expansion
In an adult whose palatal suture has fused, a surgeon makes the expansion possible and the orthodontist then widens the arch as usual. It is a shorter, smaller procedure than jaw repositioning surgery, but it is still surgery.
Who it suits: Adults with a true skeletal narrow upper jaw and a posterior crossbite they want genuinely corrected rather than camouflaged.
When is a crossbite treated, and at what age?
Children, six to ten
The best time, without much competition. The palate widens readily, the treatment is short, and the appliance is well tolerated. Correcting a crossbite here also removes the sideways shift before it has had years to shape jaw growth, which is the part that cannot be undone later.
Teenagers
Expansion is usually still possible in the early teens and becomes unreliable as the suture fuses, at an age that varies between individuals rather than arriving on a birthday. This is often folded into comprehensive treatment with braces or aligners.
Adults
Single-tooth crossbites are corrected routinely. A skeletal posterior crossbite means choosing between surgically assisted expansion and accepting the crossbite while managing its consequences — protecting the gum, monitoring wear, and treating joint symptoms if they appear.
What does it cost to fix a crossbite?
Orthodontic fees are quoted per case rather than per condition, because two people with the same diagnosis can need very different treatment. These are the factors that move the number up or down, so you know what you are being quoted on:
- Whether the correction is one appliance or comprehensive treatment of the whole bite.
- Expander alone in a child versus expander plus later braces or aligners.
- Whether surgical assistance is required, which applies almost only to adults.
- How long the retention phase runs, since a widened arch needs holding while bone fills in.
- Any referral for airway assessment, which is billed by that practice rather than here.
Ask for the fee, the payment schedule, and your insurance benefit in writing at the consultation, before you decide anything. Any orthodontic practice should give you all three without being pressed.
When should you see an orthodontist about a crossbite?
- As soon as a crossbite is noticed, at any age. This is the condition where waiting has the clearest cost.
- If a child’s jaw slides to one side to bring the teeth together, or the chin looks off-centre when biting but straight when relaxed.
- If a baby tooth has not come out and the adult tooth is erupting beside or behind it.
- If a child habitually breathes through the mouth or snores — that belongs in a conversation with a physician alongside the orthodontic examination.
Questions patients ask about crossbites
What happens if a crossbite is left untreated?
The jaw keeps closing from a shifted position. In a growing child that can produce lasting facial asymmetry; in anyone it loads the jaw joint unevenly, causes gum recession on the trapped teeth, and wears enamel on surfaces not built for contact. The crossbite rarely self-corrects.
Can a crossbite be fixed in an adult?
Single-tooth and front crossbites, yes, with braces or aligners. A narrow upper jaw in an adult needs surgically assisted expansion, because the palate has fused. That difference between a child and an adult is the strongest reason to treat a crossbite early.
How long does an expander take?
Active widening is usually a few weeks to a few months, depending on how much width is needed, followed by several months of holding while bone fills the gap. Children adapt to it quickly, and the lisp most parents worry about usually settles within a few weeks.
Does a crossbite cause jaw pain?
It can. A crossbite that forces the jaw to shift to close is one of the bite patterns most often associated with joint and muscle symptoms. Not everyone with a crossbite has pain, and not all jaw pain comes from the bite — both are assessed rather than assumed.
Can a crossbite be fixed with clear aligners?
Mild dental crossbites, yes. A skeletal narrow jaw, no — aligners tip teeth outward, which looks similar and is not the same as widening a palate. Asking which of the two applies is the right question to bring to a consultation.